USPTO Patents Application 10680019

Claims:

1. A bearing assembly, comprising:

a shaft adapted for being mounted to a complementary supporting structure; and

a bearing sleeve rotatably receiving the shaft, the bearing sleeve comprising an
inside wall surrounding the shaft, and an outer surface; wherein

the bearing sleeve comprises a plurality of first bearing members formed at the
inside wall at a first end thereof, and a plurality of second bearing members
formed at the inside wall at a second end thereof, the first bearing members
being arranged in circular fashion, the second bearing members being arranged
in circular fashion complementarily offset from the first bearing members, each
of the first and second bearing members comprises a bearing surface, the bearing
surfaces cooperatively supporting the shaft therebetween.

2. The bearing assembly as described in claim 1, wherein the bearing sleeve
defines a plurality of first and second grooves in the inside wall thereof, and the
first and second grooves are generally parallel to and equidistant from a central
axis of the bearing sleeve.

3. The bearing assembly as described in claim 2, wherein the first bearing
members are spaced from each other at regular intervals, and the second bearing
members are spaced from each other at regular intervals.

4. The bearing assembly as described in claim 3, wherein the first bearing
members and the first grooves are arranged at the first end of the bearing sleeve
in alternate fashion.

5. The bearing assembly as described in claim 4, wherein the first bearing
members extend from the first end of the bearing sleeve to inmost ends of the
second grooves respectively.

6. The bearing assembly as described in claim 3, wherein the second bearing

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members and the second grooves are arranged at the second end of the bearing
sleeve in alternate fashion.

7. The bearing assembly as described in claim 6, wherein the second bearing
members extend from the second end of the bearing sleeve to inmost ends of the
first grooves respectively.

8. The bearing assembly as described in claim 1, wherein each of the bearing
surfaces is concave, a radius of curvature of each of the bearing surface
corresponds to a central axis of the bearing sleeve, and said radius of curvature
is substantially the same as a radius of the shaft.

9. The bearing assembly as described in claim 1, wherein at least the bearing
surfaces of the first and second bearing members are made of ceramic material.

1 0. A bearing assembly, comprising:

a shaft adapted for being mounted to a complementary supporting structure;
and

a bearing sleeve rotatably receiving the shaft, the bearing sleeve comprising
an inside wall surrounding the shaft, and a plurality of bearing members
provided at the inside wall to cooperatively support the shaft therebetween,
the bearing members extending inwardly toward a central axis of the
bearing sleeve; wherein

each of the bearing members has a length less than a length of the bearing
sleeve along said axis.

11. The bearing assembly as described in claim 10, wherein the bearing members
comprises a plurality of first bearing members located at a first end of the
bearing sleeve, and a plurality of second bearing members located at an opposite
second end of the bearing sleeve.

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12. The bearing assembly as described in claim 11, wherein the first bearing
members are arranged in circular fashion, and second bearing members are
arranged in circular fashion complementarity offset from the first bearing
members.

13. The bearing assembly as described in claim 10, wherein each of the bearing
members defines a concave bearing surface thereon, the bearing surfaces
cooperatively surrounding and supporting the shaft therebetween.

14. The bearing assembly as described in claim 13, wherein at least the bearing
surfaces of the bearing members are made of ceramic material.

15. The bearing assembly as described in claim 12, wherein said first bearing
members and said second bearing members are essentially circumferentially
alternately arranged with each other while at two different cross-sectional planes
of said bearing sleeve.

16. A method of making a bearing assembly comprising:

providing a ceramic greenbody by injection molding a composite comprising
ceramic powder dispersed in a thermoplastic polymer wherein said green
body essentially defines a tube with first and second sets of protrusions on
thereof an inner face around two opposite ends in a circumferentially offset
manner with each other;

burning out the polymer and sintering said greenbody to a dense ceramic
bearing sleeve; and

grounding bearing surfaces formed on interior surfaces of said first and
second sets of protrusions by respective grinding machines adjacent thereto.

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